CODEWITHSUNDEEP
r
ksp585
ksp585

Reputation: 1770

Order of the output doesn't match the order while running the function

I have a dataset with ID numbers and number of observations. I am writing a function to display output based on the IDs the user selects. The dataset have IDs starting from 1 to 332 and their corresponding observations.

Below is the code that I wrote:

complete=function(directory,id=1:332){
    directory=read.csv(paste(path,"complete.csv",sep=""),header=TRUE,sep=",")
    as.data.frame.matrix(directory)

    mydf=na.omit(directory)

    library(plyr)

    completecount=count(mydf$ID)
    colnames(completecount)=c("ID","nobs")
    as.data.frame.matrix(completecount)
    complete=subset(completecount,select=c(ID,nobs),subset=(completecount$ID%in%id))
    return(complete)
}

When I am trying to run this

complete("specdata",4:2)

I would like to see the output in the order below based on the input above

  ID nobs
2  4  474  
3  3  243
4  2 1041

Whereas I am seeing output in the order as shown below

  ID nobs
2  2 1041
3  3  243
4  4  474

Please advise what is wrong with my code.

Thanks for your help!

Upvotes: 0

Views: 124

Answers (1)

MrFlick
MrFlick

Reputation: 206401

There's nothing in your function that ensures any order. I'm not sure if you think the %in% operator also does sorting but it does not. It returns values no matter the order the second parameter is in. The order you are returning the rows is the order they were in in the original table.

Unlike %in%, match() actually does return values in order. You could do something like 

library(plyr)

complete=function(directory,id=1:332){
    directory=read.csv(paste(path,"complete.csv",sep=""),header=TRUE,sep=",")
    as.data.frame.matrix(directory)

    mydf=na.omit(directory)

    completecount=count(mydf$ID)
    colnames(completecount)=c("ID","nobs")
    as.data.frame.matrix(completecount)
    return(completecount[match(id, completecount$ID), ])
}

This will pluck rows out of completecount in the order they they are passed to the function.

Upvotes: 2

Related Questions